<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Http\UploadedFile;
use Illuminate\Validation\ValidationException;
use PhpOffice\PhpSpreadsheet\IOFactory;
use Throwable;

/**
 * 科目映射表导入。
 *
 * 兼容两套表头：
 *   A 旧版 9 列：平台 | 账单项目 | 财务备注 | 票据 | 大类 | 借/贷（借） | 借/贷（二级） | 借/贷（借） | 借/贷（二级）
 *     —— 「借/贷（借）」重复出现两次，靠位置区分：前两列是借方、后两列是贷方
 *   B 新版 10 列：平台 | 账单项目 | 财务备注 | 票据口径 | 大类 | 借方科目 | 借方二级 | 贷方科目 | 贷方二级 | 方向基准
 *
 * 没有方向基准列时，按大类推导（费用/保证金/推广/暂挂/营业外支出/提现 → 支出基准；收入/转账 → 收入基准）。
 */
class AccountMappingWorkbookImporter
{
    private const ALIASES = [
        'platform' => ['平台', '平台名称', '渠道'],
        'item' => ['账单项目', '项目', '账单类型', '交易类型', '收支项目'],
        'memo' => ['业务备注', '财务备注', '二次备注', '业务备注关键词', '账务备注', '备注'],
        'goods' => ['商品名称关键词', '商品名称', '商品描述', '货品名称'],
        'invoice' => ['票据口径', '票据', '票据类型', '发票'],
        'category' => ['财务类型', '大类', '业务性质', '科目大类', '分类'],
        'feeMemo' => ['费用备注', '费用说明', '费用备注说明'],
        'basis' => ['方向基准', '基准'],
        'dAcct' => ['借方科目', '借/贷（借）', '借/贷(借)', '借方'],
        'dSub' => ['借方二级'],
        'cAcct' => ['贷方科目'],
        'cSub' => ['贷方二级'],
    ];

    private const INVOICE_MAP = [
        '0' => '不开票',
        '0.00' => '不开票',
        '0%' => '不开票',
        '0.06' => '0.06',
        '6%' => '0.06',
        '06' => '0.06',
        '可开6%专票' => '0.06',
        '开6%专票' => '0.06',
        '不开票' => '不开票',
        '不开票（无票）' => '不开票',
        '不开票(无票)' => '不开票',
        '无票' => '不开票',
        '-' => '-',
        '—' => '-',
        '不涉及' => '-',
    ];

    /**
     * @return array{rows:array<int,array<string,string>>,header_row:int,sheet:string}
     */
    public function parse(UploadedFile $file): array
    {
        $extension = mb_strtolower((string) $file->getClientOriginalExtension());

        try {
            $readerType = match ($extension) {
                'xlsx' => 'Xlsx',
                'xls' => 'Xls',
                'csv' => 'Csv',
                default => throw new \RuntimeException('Unsupported workbook format.'),
            };

            $reader = IOFactory::createReader($readerType);
            if ($readerType === 'Csv') {
                $reader->setInputEncoding('UTF-8');
            }
            $spreadsheet = $reader->load($file->getRealPath());
        } catch (Throwable) {
            throw ValidationException::withMessages([
                'import' => '读不出这个文件，请确认是 xlsx / xls / csv，且没有损坏。',
            ]);
        }

        try {
            $best = null;
            foreach ($spreadsheet->getWorksheetIterator() as $sheet) {
                $grid = $sheet->toArray(null, true, false, false);
                $grid = array_values(array_filter($grid, static fn (array $row): bool => $row !== []));
                if ($grid === []) {
                    continue;
                }
                $headerRow = $this->locateHeader($grid);
                $score = $headerRow === null ? -1 : count(array_filter($this->mapHeader($grid[$headerRow])));
                if ($score <= 0) {
                    continue;
                }
                if ($best === null || $score > $best['score']) {
                    $best = ['score' => $score, 'grid' => $grid, 'header_row' => $headerRow, 'sheet' => $sheet->getTitle()];
                }
            }
        } finally {
            $spreadsheet->disconnectWorksheets();
        }

        if ($best === null) {
            throw ValidationException::withMessages([
                'import' => '没找到表头。至少要有一列「平台」和一列「账单项目」，以及借方、贷方两组科目列。',
            ]);
        }

        $columns = $this->mapHeader($best['grid'][$best['header_row']]);
        $rows = [];
        foreach (array_slice($best['grid'], $best['header_row'] + 1) as $gridRow) {
            $row = [];
            foreach ($columns as $field => $index) {
                if ($index === null) {
                    $row[$field] = '';
                    continue;
                }
                $value = $gridRow[$index] ?? '';
                $row[$field] = trim((string) (is_scalar($value) ? $value : ''));
            }
            if ($row['platform'] === '' && $row['item'] === '') {
                continue;
            }
            $row['invoice'] = $this->normalizeInvoice($row['invoice']);
            $row = $this->inferBasis($row);
            $rows[] = $row;
        }

        return ['rows' => $rows, 'header_row' => $best['header_row'], 'sheet' => $best['sheet']];
    }

    /** @param array<int,mixed> $row */
    private function locateHeader(array $grid): ?int
    {
        foreach ($grid as $index => $row) {
            if (count(array_filter($this->mapHeader($row))) >= 3) {
                return $index;
            }
        }

        return null;
    }

    /**
     * @param array<int,mixed> $header
     * @return array<string,int|null>
     */
    private function mapHeader(array $header): array
    {
        $cells = [];
        foreach ($header as $index => $value) {
            $cells[$index] = $this->normalizeHeader((string) (is_scalar($value) ? $value : ''));
        }

        $columns = [];
        foreach (self::ALIASES as $field => $aliases) {
            $columns[$field] = null;
            foreach ($aliases as $alias) {
                $needle = $this->normalizeHeader($alias);
                $found = array_search($needle, $cells, true);
                if ($found !== false) {
                    $columns[$field] = (int) $found;
                    break;
                }
            }
        }

        // 旧版表头「借/贷（借）」出现两次、没有「贷方科目」：借方组命中的那列起，往后取 4 列。
        $dAcct = $columns['dAcct'];
        if ($dAcct !== null && $columns['dSub'] === null && $columns['cAcct'] === null && $columns['cSub'] === null) {
            $columns['dSub'] = $dAcct + 1;
            $columns['cAcct'] = $dAcct + 2;
            $columns['cSub'] = $dAcct + 3;
        } elseif ($dAcct === null && $columns['cAcct'] !== null && $columns['dSub'] === null) {
            $columns['dAcct'] = max($columns['cAcct'] - 2, 0);
            $columns['dSub'] = max($columns['cAcct'] - 1, 0);
            $columns['cSub'] = $columns['cAcct'] + 1;
        }

        return $columns;
    }

    private function normalizeHeader(string $value): string
    {
        $value = str_replace(['（', '）', '(', ')', ' '], ['(', ')', '(', ')', ''], $value);

        return trim($value);
    }

    private function normalizeInvoice(string $value): string
    {
        $value = trim($value);
        if ($value === '') {
            return '';
        }

        return self::INVOICE_MAP[$value] ?? $value;
    }

    /** @param array<string,string> $row @return array<string,string> */
    private function inferBasis(array $row): array
    {
        $basis = trim((string) ($row['basis'] ?? ''));
        if ($basis === '') {
            $basis = AccountMappingStore::CATEGORY_BASIS[trim((string) $row['category'])] ?? '';
        }
        $row['basis'] = $basis;

        return $row;
    }
}